Power Query use List Product in let statement

Hi,
I've just about got what i wanted to acheive in I have tablle of 1 and 0, and want to replace the 1 with the corresponding column value form another table.

the code I have so fat is ; LK = singe row table with replacement values.

Table.AddColumn(Source, "Custom", each let
 Tlist = Record.ToList(_) , 
   LKlist = Record.ToList( LK{0} ) , 
   zip = List.Zip( { Tlist, LKlist } ) , 
   tzip = List.Transform( zip, (A)=> List.Product(A) ) 
in 
tzip)

This give me a column of lists which I cant then use Table transform columns with List Product,
But have been trying to put this final step in the above and keep getting it wrong.

Attached , Problem query = AddColumn